Module: OTP::Base32

Defined in:
lib/otp/base32.rb

Constant Summary collapse

ENCODE_CHARS = 
%w(
  A B C D E F G H I J K L M N O P
  Q R S T U V W X Y Z 2 3 4 5 6 7
)
DECODE_MAP = 
{
  "A"=>0,  "B"=>1,  "C"=>2,  "D"=>3,  "E"=>4,  "F"=>5,  "G"=>6,  "H"=>7,
  "I"=>8,  "J"=>9,  "K"=>10, "L"=>11, "M"=>12, "N"=>13, "O"=>14, "P"=>15,
  "Q"=>16, "R"=>17, "S"=>18, "T"=>19, "U"=>20, "V"=>21, "W"=>22, "X"=>23,
  "Y"=>24, "Z"=>25, "2"=>26, "3"=>27, "4"=>28, "5"=>29, "6"=>30, "7"=>31,
  "0"=>14, "1"=>11, "8"=>1,                        # mistyped chars
  " "=>-2, "-"=>-2, "\n"=>-2, "\r"=>-2, "\t"=>-2,  # separators
  "="=>-1,                                         # padding
}

Class Method Summary collapse

Class Method Details

.decode(chars) ⇒ Object 



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# File 'lib/otp/base32.rb', line 41

def decode(chars)
  return nil unless chars
  ret = "".force_encoding("binary")
  chars = chars.upcase
  buffer = buffered = 0
  chars.each_char do |c|
    d = DECODE_MAP[c]
    raise ArgumentError, "invalid char: #{c}" if d.nil?
    next if d == -2
    break if d == -1
    buffer = (buffer << 5) | d
    buffered += 5
    next if buffered < 8
    ret << ((buffer >> (buffered - 8)) & 0xff)
    buffered -= 8
  end
  return ret
end

.encode(bytes) ⇒ Object 



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# File 'lib/otp/base32.rb', line 20

def encode(bytes)
  return nil unless bytes
  bytes = bytes.dup.force_encoding("binary")
  ret = ""
  offset = buffer = buffered = 0
  while offset < bytes.length
    buffer = ((buffer << 8) | bytes[offset].ord)
    buffered += 8
    offset += 1
    while buffered >= 5
      ret << ENCODE_CHARS[buffer >> (buffered - 5)]
      buffered -= 5
      buffer &= (0xff >> (8 - buffered))
    end
  end
  if buffered > 0
    ret << ENCODE_CHARS[buffer << (5 - buffered)]
  end
  return ret
end